Sotheby's adopts 'poison pill' after Dan Loeb raises stake

Sotheby's, the big auction house, has adopted a poison pill after activist investor Dan Loeb called for changes in how the company is run.

Sotheby's adopted a "poison pill" to ward off an unwanted takeover, two days after activist investor Daniel Loeb's Third Point announced that it raised its stake in the auctioneer and called for its chief executive, William Ruprecht, to step down.

The company said the shareholder rights plan would be triggered if a person or group acquired 10 percent or more of its shares.

Third Point has raised its stake to 9.3 percent, making it Sotheby's largest shareholder.